Interlaboratory evaluation of the C3H/10T1/2 cell transformation assay

The C3H/10T1/2 transformation assay was evaluated for its responsiveness and interlaboratory reproducibility. Two laboratories participated in this study and tested a series of 46 chemicals. The majority of these chemicals were tested under code. Of the 46 chemicals tested, seven were determined to be active in both laboratories, and 14 were determined to be inactive. When the total number of chemicals is adjusted for assays considered "no test" in either one or both laboratories as well as for tests of chemicals yielding positive results in only one laboratory, reproducible responses were obtained for 21/35, or 60%, of the chemicals tested.